Currently in the United States, testing of new plumbing systems is required by plumbing codes to insure that there are no leaks, bad fittings, bad connections, cracked pipes, etc. The waste and vent system is tested by filling the pipes with water or air. These tests require 5 lbs. or greater PSI (per square inch) of air or 10 feet of head pressure for water. The system must hold this pressure for the length of time determined by local authorities. For example, in Georgia this length of time is approximately 15 minutes.
Test tees are currently installed in plumbing systems where new pipes meet with the existing or previously inspected systems, such as an underground system tied into a city tap. The test tee would be installed between the end of the city tap and the beginning of the new system. This would allow a plug to be placed in the new system side of the tee so the system can be tested. The tee is most often used when the previously inspected underground waste system comes through a concrete slab. It would be connected between the pipes penetrating the slab and the continuation of the above ground system. This would allow a test to be administered from this point and above without retesting the underground system.
The tee fitting is sometimes referred to as a cleanout tee. It is simply a T shaped fitting with a threaded opening for a removable plug. Tee fittings comprise a tubular section extending between a first and a second opposing openings axially aligned with each other; and a third opening communicating with the tubular section of the tee fitting.
When the tee fitting is used in the testing application the plug is removed and a rubber inflatable ball or mechanical compression plug is inserted into the tee on the new side to create a blockage to the waste and vent system so it can be filled with air or water for testing. Once all testing has been completed and the system is functional the threaded plug may be removed, when accessible, and the opening maybe used to cleanout any possible blockage below this point in the future,
The problem that often exists with this process is that these rubber test balls sometimes do not hold applied air or water pressure dropping below the code requirement. Improper installation or positioning will not allow for a secure seal and often causes the test to lose pressure. The inflatable test balls are made of natural rubber and have a limited life expectancy causing failure and replacement can be costly. Mechanical plugs have been known to fail if not properly installed and in some instances can crack pipes or fittings.
To find any of these problems in a large system that is being prepared for inspection can be very time consuming especially when testing with air. The failing test device is not always immediately recognizable. Once the problem is located the ball must be reinstalled and re-inflated. If the ball appears faulty, a new ball must be utilized and the system completely retested. This process is very intensive and could be the cause for a failed inspection potentially delaying a project schedule.
Therefore, there is a tremendous need for a true test tee that is sure hold pressure for the length of time determined by local authorities to complete testing of a plumbing system.